This invention relates to an eccentric pin on a scroll compressor drive shaft, and more specifically, to a method of forming a drive surface on the eccentric pin.
Scroll compressors utilize drive shafts that have an end with an eccentric pin, which is displaced from the rotational axis of the drive shaft. The eccentric pin is received within a bore in a slider block which is, in turn, received within a portion of an orbiting scroll, as is well know in the art. During rotation of the drive shaft, the eccentric pin engages the slider block and moves the orbiting scroll through an orbital path.
The eccentric pin has a generally cylindrical outer surface with a drive surface formed along the length of a portion of the outer surface. The drive surface is generally flat with a slight crown in the middle for providing single line contact with the slider block. The drive surface must have a relatively smooth surface finish to minimize the friction between the eccentric pin and the slider block. Previously, to form the drive surface the drive shaft had to be moved to a first machining operation where a flat was broached onto the eccentric pin. Next, the drive shaft had to be moved to a second machining operation where the crown was then formed on the flat by a finish grinding operation, which also provided the desired surface finish. Forming a drive surface with a crown in two separate operations resulted in increased labor and tooling costs. Therefore, what is needed is a more efficient method of forming a finished drive surface with a crown.